--- category: Interoperability description: Cross-chain communication via XCM, asset transfers, HRMP channels, and bridging to external networks. page_count: 12 token_estimate: 1954 updated: '2026-06-25T12:38:13.291384+00:00' --- ## Bridge Hub https://docs.polkadot.com/reference/polkadot-hub/bridging.md Learn about the Bridge Hub system parachain, a parachain that facilitates the interactions from Polkadot to the rest of Web3. ### Sections - Introduction `#introduction` - Trustless Bridging `#trustless-bridging` - Bridging Components `#bridging-components` - Ethereum-Specific Support `#ethereum-specific-support` - Deployed Bridges `#deployed-bridges` - Where to Go Next `#where-to-go-next` --- ## Get Started with XCM https://docs.polkadot.com/parachains/interoperability/get-started.md Unlock blockchain interoperability with XCM — Polkadot's Cross-Consensus Messaging format for cross-chain interactions. ### Sections - Introduction `#introduction` - Messaging Format `#messaging-format` - The Four Principles of XCM `#the-four-principles-of-xcm` - The XCM Tech Stack `#the-xcm-tech-stack` - Core Functionalities of XCM `#core-functionalities-of-xcm` - XCM Example `#xcm-example` - Overview `#overview` --- ## Interoperability https://docs.polkadot.com/reference/parachains/interoperability.md Explore the importance of interoperability in the Polkadot ecosystem, covering XCM, bridges, and cross-chain communication. ### Sections - Introduction `#introduction` - Why Interoperability Matters `#why-interoperability-matters` - Key Mechanisms for Interoperability `#key-mechanisms-for-interoperability` - Cross-Consensus Messaging (XCM): The Backbone of Communication `#cross-consensus-messaging-xcm-the-backbone-of-communication` - Bridges: Connecting External Networks `#bridges-connecting-external-networks` - The Polkadot Advantage `#the-polkadot-advantage` - Looking Ahead `#looking-ahead` --- ## Opening HRMP Channels Between Parachains https://docs.polkadot.com/parachains/interoperability/channels-between-parachains.md Learn how to open HRMP channels between parachains on Polkadot. Discover the step-by-step process for establishing uni- and bidirectional communication. ### Sections - Introduction `#introduction` - Prerequisites `#prerequisites` - Procedure to Initiate an HRMP Channel `#procedure-to-initiate-an-hrmp-channel` - Fund Sender Sovereign Account `#fund-sender-sovereign-account` - Create Channel Opening Extrinsic `#create-channel-opening-extrinsic` - Craft and Submit the XCM Message from the Sender `#craft-and-submit-the-xcm-message-from-the-sender` - Procedure to Accept an HRMP Channel `#procedure-to-accept-an-hrmp-channel` - Fund Receiver Sovereign Account `#fund-receiver-sovereign-account` - Create Channel Accepting Extrinsic `#create-channel-accepting-extrinsic` - Craft and Submit the XCM Message from the Receiver `#craft-and-submit-the-xcm-message-from-the-receiver` --- ## Opening HRMP Channels with System Parachains https://docs.polkadot.com/parachains/interoperability/channels-with-system-parachains.md Learn how to open HRMP channels with Polkadot system parachains. Discover the process for establishing bi-directional communication using a single XCM message. ### Sections - Introduction `#introduction` - Prerequisites `#prerequisites` - Procedure to Establish an HRMP Channel `#procedure-to-establish-an-hrmp-channel` - Fund Parachain Sovereign Account `#fund-parachain-sovereign-account` - Create Establish Channel with System Extrinsic `#create-establish-channel-with-system-extrinsic` - Craft and Submit the XCM Message `#craft-and-submit-the-xcm-message` --- ## ParaSpell XCM SDK https://docs.polkadot.com/reference/tools/paraspell.md A powerful open-source library that simplifies XCM integration, enabling developers to easily build interoperable dApps on Polkadot. ### Sections - Introduction `#introduction` - ParaSpell XCM SDK `#paraspell-xcm-sdk` - Install ParaSpell `#install-paraspell` - Where to Go Next `#where-to-go-next` --- ## Register a Foreign Asset https://docs.polkadot.com/chain-interactions/token-operations/register-foreign-asset.md Learn step-by-step how to register a foreign asset on Polkadot Hub and the origin parachain to enable cross-chain token transfers. ### Sections - Introduction `#introduction` - Prerequisites `#prerequisites` - Register a Foreign Asset `#register-a-foreign-asset` - Polkadot Hub `#polkadot-hub` - Source Parachain `#source-parachain` - Asset Registration Verification `#asset-registration-verification` - Test Environment Setup `#test-environment-setup` --- ## Replay and Dry Run XCMs https://docs.polkadot.com/chain-interactions/send-transactions/interoperability/debug-and-preview-xcms.md Replay and dry-run XCMs using Chopsticks with full logging enabled. Diagnose issues, trace message flow, and debug complex cross-chain interactions. ### Sections - Introduction `#introduction` - Prerequisites `#prerequisites` - Set Up Your Project `#set-up-your-project` - Capture the XCM to Replay `#capture-the-xcm-to-replay` - Fork the Relevant Chains `#fork-the-relevant-chains` - Set the Block Numbers `#set-the-block-numbers` - Enable Logging and Wasm Override `#enable-logging-and-wasm-override` - Identify and Extract the XCM `#identify-and-extract-the-xcm` - Replay the XCM `#replay-the-xcm` - Add the Polkadot Hub Descriptor `#add-the-polkadot-hub-descriptor` - Create a Replay Script `#create-a-replay-script` - Execute the Replay Script `#execute-the-replay-script` - Expected Output `#expected-output` - Dry Run the XCM `#dry-run-the-xcm` - Create a Dry Run Script `#create-a-dry-run-script` - Execute the Dry Run Script `#execute-the-dry-run-script` - Review and Debug `#review-and-debug` - Where to Go Next `#where-to-go-next` --- ## Transfer Assets Between Parachains https://docs.polkadot.com/chain-interactions/send-transactions/interoperability/transfer-assets-parachains.md A step-by-step guide to using the ParaSpell XCM SDK to build, verify, and execute a transfer from one Parachain to another. ### Sections - Introduction `#introduction` - Prerequisites `#prerequisites` - Initialize Your Project `#initialize-your-project` - Build a Token Transfer Transaction `#build-a-token-transfer-transaction` - Perform a Dry Run `#perform-a-dry-run` - Verify the Existential Deposit `#verify-the-existential-deposit` - Get Transfer Info and Fee Estimates `#get-transfer-info-and-fee-estimates` - Next Steps `#next-steps` --- ## Transfer Assets from Ethereum into Polkadot https://docs.polkadot.com/chain-interactions/send-transactions/interoperability/transfer-assets-into-polkadot.md A step-by-step guide to bridging assets from Ethereum to Polkadot using the ParaSpell XCM SDK and Snowbridge. ### Sections - Introduction `#introduction` - How the Bridge Works `#how-the-bridge-works` - Prerequisites `#prerequisites` - Prepare Tokens for Bridging `#prepare-tokens-for-bridging` - Initialize Your Project `#initialize-your-project` - Approve Tokens for Bridging `#approve-tokens-for-bridging` - Build and Execute the Bridge Transfer `#build-and-execute-the-bridge-transfer` - Monitor the Transfer `#monitor-the-transfer` - Where to Go Next `#where-to-go-next` --- ## XCM Fee Estimation https://docs.polkadot.com/chain-interactions/send-transactions/interoperability/estimate-xcm-fees.md This tutorial demonstrates how to estimate the fees for teleporting assets from the Polkadot Hub TestNet to the Paseo People Chain. ### Sections - Introduction `#introduction` - Fee Mechanism `#fee-mechanism` - Environment Setup `#environment-setup` - Client and API Setup `#client-and-api-setup` - Fee Estimation Function `#fee-estimation-function` - Complete Implementation `#complete-implementation` - Full Code `#full-code` - Running the Script `#running-the-script` - Conclusion `#conclusion` --- ## XCM Tools https://docs.polkadot.com/reference/tools/xcm-tools.md Explore essential XCM tools across Polkadot, crafted to enhance cross-chain functionality and integration within the ecosystem. ### Sections - Introduction `#introduction` - Popular XCM Tools `#popular-xcm-tools` - Moonsong Labs XCM Tools `#moonsong-labs-xcm-tools` - ParaSpell `#paraspell` - Astar XCM Tools `#astar-xcm-tools` - Chopsticks `#chopsticks` - Moonbeam XCM SDK `#moonbeam-xcm-sdk`